Biotransformation of cyanide has important environmental and occupational health implications, as it is a constant respiratory pollutant due to inhalation of hydrogen cyanide fumes from tobacco smoke, and a hazardous industrial pollutant of our drinking water and streams. Cyanide is present in cassava, a staple food, predominantly in Africa and South America. Although the acute toxicity of cyanide is well recognized, chronic cyanide intoxication may be a much health hazard, as it is an occupational hazard and can produce neurological diseases and blindness. Low cyanide levels have been implicated as the etiology of Tropical neurotropic Ataxia in man, producing neurological lesion by a demyelinization of nerves. Several laboratories have proposed that cyanide may precipitate demyelinization of the optic nerve, and the cyanide content of tobacco smoke has been postulated as the etiology of tobacco amblyopia. There is a paucity of information on the metabolism of cyanide and the information which is available warrants further investigation. The proposed research will focus primarily on the metabolic disposition of cyanide and on binding and spectroscopic studies of the enzyme involved in detoxification.